I don't think rca's change. They go in the usual left and right or colored plug ins. It's the wiring that coming out of the amps that changes/crosses. Negative out of one side positive out of the other.

The nomanclature silkscreened on the end of the amplifier shows to use the front RCA inputs when bridging. But, you really need to read the instruction manual that ships with the amplifier or download it off the Wetsounds site. There are several other configuration switches and related issues explained in the manual that you definitely will need to know about.